There are a lot of secrets in the world of Prey, many of which are locked behind passcodes, locked doors, or impenetrable vaults. One of the first safes you come across can be found in the Simulation Debriefing room right after you escape from your apartment. After you’ve broken out of your home, head around the back until you reach an area with a bunch of computers and lighting. Follow the path to the back right room labeled “Simulation Debriefing” and head inside.
To your right, there is going to be a safe that requires either the right passcode or a high enough hacking skill to open. Behind you is a whiteboard with the code scribbled out, however, you don’t need to learn the code in-game to use it. Simply go over to the safe and input 5150 to unlock it and obtain the rare contents inside. If you are curious as to where you actually learn the code, it can be found in Morgan’s office via the video later in the game.
Figuring it out this way will then require you to do a lot of backtracking, so it’s just worth it to open the safe and get the items now. You will want to have all the advantages you can muster in Prey, so don’t feel bad if you just unlock the safe now.